Here is an answer provided by our respected expert and moderator Xpcman.
"This type of problem is normally hardware in nature.
Does the laptop play the Windows "welcome" sound? If you had the sound before and don't now, then you laptop may need major repairs.
Can you connect an external monitor to the laptop? Remember that you will need to activate the video port with a Function Key before you can expect to see an image on the external display. I
Try to shine a bright light at an angle on the screen when the PC is on. If you see a faint image, then your "backlight" or "inverter" is broken. "
Hope this helps